<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>计数器</title>
</head>
<body>
    <div id="app">
        <div class="input-num">
            <button @click="sub">-</button>
            <span>{{num}}</span>
            <button @click="add">+</button>
        </div>
    </div>

    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"> </script>
    <script>
        //创建vue实例
        var app = new Vue({
        el: '#app',
        data:{
            num:1
        },
        methods:{
            add:function(){
                // console.log('add');
                if (this.num<10) {
                    this.num++;
                }
                else{
                    alert("别点啦，最大啦");
                }
            },
            sub:function(){
                // console.log('sub');
                if (this.num>0) {
                    this.num--;
                }
                else{
                    alert("别点啦，最小啦");
                }

            }
        }
})
    </script>
</body>
</html>